The present invention relates to a deformation bar for the energy-absorbing support of a knee restraint which is attached to an instrument panel, and has a load-distributing panel and an impact-absorption member arranged in front of the latter. The profiled deformation bar has an approximately V-shaped extent, of which one leg serves to support the knee restraint and the other leg is supported on a transverse carrier running in the transverse direction of the vehicle and fixed to the bodywork. The deformation bar is provided with two deformation zones, of which the first is arranged in the region of the section connecting the two legs to one another and the second is arranged at a bending location in the region of the load-distributing panel, which is arranged in front and connects two deformation members to one another.
A knee restraint supported via such deformation bars is shown in U.S. Pat. No. 4,978,136. The load-distributing panel is connected, via deformation members, to the deformation bars, of which the V-opening is oriented upwards. The instrument-panel leg end of each deformation bar is additionally supported via a tube piece which is fixed at one end. This results, in the event of knee impact, in local penetration of the upwardly moving knees and, in the case of correspondingly tall individuals, in a hazardous support of the knees on the tube piece, which prevents sideways movements of the load-distributing panel in the event of oblique impact of the knees.
An object of the present invention is to configure the deformation bar, and attach it to the load-distributing panel, to achieve a hazard-free support, irrespective of the height of an individual, of the knees, which do not move upwards in the event of impact, with a high energy-absorption capacity, even in the event of oblique impact of the knees.
This object has been achieved in accordance with the present invention by providing that a V-opening of the V-shaped deformation bar, in an installed position of the latter, is oriented forward and obliquely downward, away from the instrument panel, and a third deformation zone is arranged at an end of the deformation bar remote from the instrument panel so as to come into action, by way of a bending-off movement in the counterclockwise direction, when energy-absorption capacity of the first deformation zone has been utilized, and the legs of the deformation bar come to rest against one another. Only when energy-absorption capacity of the third deformation zone has been utilized, the second deformation zone, together with the load-distributing panel which bounds the instrument panel rearwardly at least in a knee-supporting region and is supported directly on the one leg of the deformation bar up to the first deformation zone of the latter, is transferred into a position approximating an extended position.
In one currently preferred embodiment of the present invention, the energy-absorption capacity of the third deformation zone is particularly well utilized if, at its end remote from the instrument panel, each deformation bar is joined to the transverse carrier and connected thereto. Thereby, upon deformation, the associated third deformation zone wraps around the transverse carrier beyond the perpendicular.
When the transverse carrier is arranged at a different level, that end of each approximately V-shaped deformation bar remote from the instrument panel is adjoined by a further arcuate and non-deformable bar section which is fastened non-releasably to the bottom of the transverse carrier. Overall, this results in an approximately S-shaped configuration for the deformation bar.
Each deformation bar can be provided with a hat-shaped profile. The deformation zones are produced by a specific reduction in the web height and/or the material thickness. If the deformation bar is configured as a light-metal diecasting part, then the deformation zones can be produced particularly easily.
It is, however, also within the scope of the present invention for each deformation to have a hat-shaped profile, and for the deformation zones to be produced in that, adjoining the zones, the hat-shaped profile has reinforcements in the form of beads and/or wall-doubling structure.
The impact-absorption member can be configured as a shell-like carrier part which is positioned on the front surface of the instrument panel, facing the vehicle interior. A cavity is left therebetween, and extends at least over the region where the deformation bar rests against the instrument panel. An energy-absorption element is formed by an energy-absorbing insert which fills the cavity between the carrier part and the instrument panel. In this manner, residual energy can still be absorbed by the insert even after the energy-absorption capacity of the deformation bars has been exhausted.